CN1682134A

CN1682134A - Plastic optical fiber

Info

Publication number: CN1682134A
Application number: CNA038218445A
Authority: CN
Inventors: 小池康博; 石榑崇明; 室伏英伸; 渡边勇仁; 大西状
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2002-09-12
Filing date: 2003-09-11
Publication date: 2005-10-12
Also published as: US7058271B2; AU2003262088A1; EP1538467A1; JPWO2004025340A1; US20050207714A1; KR20050035537A; WO2004025340A1

Abstract

A plastic optical fiber low in attenuation in a high order mode and small in mode dispersion, is presented. The plastic optical fiber comprises at least a core and a clad surrounding the core, characterized in that the core has a refractive index which gradually decreases from the core center towards the outside in the radial direction of the plastic optical fiber, and the refractive index of the clad is lower than the refractive index of the core center and higher than the refractive index of the core periphery.

Description

Plastic optical fiber

Technical field

The present invention relates to the to communicate by letter plastic optical fiber of usefulness is particularly to the improvement of the information transmission performance of multimode optical fiber.

Background technology

For increase corresponding in recent years information communication capacity, in the middle wire system of existing Japan, lay quartzy class single-mode fiber network, finished total digitalization.Quartzy class single-mode fiber because its transmission loss is low, can the long-distance transmissions light signal, so be desirable transmission medium, but for more high-speed communication, the diameter in its core zone is designed to about 5-10 μ m.But for rigidity, diameter must be reduced because of quartz, could be crooked, also there is extremely fragile realistic problem.

In order in so little core zone, to carry out incident, connection and the branch of light signal, so require very high calibration (alignment) technology, with spending significant cost on comprehensive laying of quartzy class single-mode fiber, family etc. laid all be difficult to reach.

On the other hand, polymer optical fiber (POF) is so the cost of material is low because the starting material of formation optical fiber are made of polymkeric substance, compare with quartzy type optical fiber, can carry out heavy caliberization (200-1000 μ m), in addition, even heavy caliber optical fiber like this, because the flexibility that polymeric material had, bendability is strong, has very excellent characteristic.Because utilize such POF carry out heavy caliberization, can extremely easily carry out the injecting of light signal, connection and branch.

The graded-index of achievement in research up to now (abbreviating GI as) type POF is from core centre laterally, radial refractive index along above-mentioned plastic optical fiber reduces gradually, the refractive index of above-mentioned cladding part is lower than the refractive index of above-mentioned core centre, the plastic optical fiber that material is made of poly-methyl methacrylate base ester (abbreviating PMMA as) (reference example such as open the flat 6-186441 of communique number of Japan's special permission, open the flat 6-186442 of communique number of Japan's special permission, open the flat 7-27928 of communique number of Japan's special permission).This GI type POF, as shown in Figure 1, the outgoing wave shape after the 100m transmission is subjected to the different influence of mould, has formed the waveform that enlarges slightly time of arrival, and has formed the shape about the same with the incident wave shape (waveform of the solid line of Fig. 1).From this point, the modal dispersion of GI type POF is little, compares with in the past SI type (ladder refractive index type, step-index) POF, communication speed can be improved 2 figure places, is epoch-making product.

In addition, consider and being connected of the quartzy type optical fiber of trunk fiber, as the trial that will reduce, made that the hydrogen atom in the polymer molecule is replaced into POF (open the flat 10-293215 of communique number of reference example such as open the flat 10-268146 of communique number of Japan's special permission, Japan's special permission) than its heavy D atom or fluorine atom with the transmission loss of the POF of the wavelength 1.55 μ m of the minimum loss of quartzy type optical fiber.Its result can make following POF: absorbing wavelength moves to long wavelength's one side, can realize low lossization with wavelength 1.55 μ m, and transmission loss is very low in from the visible region of broad near infrared range.

But owing to adopt these materials to realize transparences, it is more outstanding to make employing PMMA optical fiber in the past be hidden in the problem of dispersion of higher mode behind.Specifically, as shown in Figure 1, on the outgoing waveform, the output that is considered to the influence of Gao Mo lags by clear showing (the circular waveform of white among Fig. 1).Though can expect that with such fluorine type optical fiber etc. transparence is cut down transmission loss, still, the new problem that communication speed obviously reduces comes out.

For this reason, people pump up to keeping the low transmission loss, with the transportation lag shortening of higher mode and the exploitation that can improve the technology of communication speed.

The present invention is problem for solving above-mentioned problem in the past to arrive following purpose.That is, problem of the present invention is: provide a kind of higher mode transmission loss little, the plastic optical fiber that modal dispersion is little.

Summary of the invention

Carried out found that of further investigation according to above-mentioned purpose: the present inventor just can arrive purpose of the present invention by following formation.

1. plastic optical fiber, it is the plastic optical fiber that has the cladding part of fiber core part and this fiber core part periphery at least, it is characterized in that, from core centre laterally, the refractive index of above-mentioned fiber core part radially reduces towards the outside from core centre gradually along above-mentioned plastic optical fiber; The refractive index of above-mentioned cladding part is lower than the refractive index of above-mentioned core centre, and is higher than the refractive index of core periphery.

2. plastic optical fiber according to claim 1 is characterized in that, has pars intermedia between above-mentioned core periphery and the above-mentioned cladding part, and the refractive index of this pars intermedia is lower than the refractive index of above-mentioned cladding part.

3. according to above-mentioned 1 or 2 described plastic optical fibers, it is characterized in that above-mentioned fiber core part contains and can form by the non-polymerization compound that concentration gradient forms index distribution.

4. according to above-mentioned 1,2 or 3 described plastic optical fibers, it is characterized in that above-mentioned fiber core part and above-mentioned cladding part independently contain one or more the polymkeric substance that is selected from acrylic polymers, polystyrene, polynorbornene, polycarbonate, polyimide and the polyester respectively.

5. according to above-mentioned 3 or 4 described plastic optical fibers, it is characterized in that above-mentioned non-polymerization compound is one or more the compound that is selected from diphenyl sulfide, Ergol, triphenyl phosphate, dibutyl phthalate and the tricresyl phosphate.

6. according to above-mentioned 1,2 or 3 described plastic optical fibers, it is characterized in that above-mentioned fiber core part and above-mentioned cladding part independently contain respectively and do not have the fluoropolymer of hydrogen atom in fact and form.

7. according to above-mentioned 3 or 6 described plastic optical fibers, it is characterized in that above-mentioned non-polymerization compound is the fluorine-containing polycyclic compound that has carbocyclic ring more than 3 or 3 or heterocycle and do not have hydrogen atom in fact.

8. according to above-mentioned 3 or 6 described plastic optical fibers, it is characterized in that above-mentioned non-polymerization compound is the chlorotrifluoroethylene oligomer.

Description of drawings

Fig. 1 is the figure that shows the outgoing wave shape after incident wave shape and 100m transmit.

Fig. 2 shows the cross section of W type POF and the figure of index distribution.

The figure of the refractive index distribution curve when Fig. 3 is the parameter g variation that shows in the formula (1) that makes the expression refractive index distribution curve.

Fig. 4 is the figure that shows the refractive index distribution curve when the parameter ρ that makes in the following formula (1) changes.

Fig. 5 is the longitudinal section that is applicable to the wire-drawing frame of the plastic optical fiber mother metal wire drawing that the present invention is made.

Fig. 6 be expression embodiment make have pars intermedia, matrix polymer is the refractive index profile of the W type POF of PMMA.

Fig. 7 be expression embodiment make do not have pars intermedia, matrix polymer is the refractive index profile of the GI type POF of PMMA.

Fig. 8 is that the expression matrix polymer is the figure of mould dependence loss of the POF of PMMA.

Fig. 9 is the figure that shows the measurement result of mould dependence time delay.

(label declaration)

A is a core centre; B is a fiber core part; C is a pars intermedia; D is a cladding part; r ₀It is core centre; R1 is the separation of fiber core part and pars intermedia; R2 is the separation of pars intermedia and cladding part; The 410th, wire-drawing frame; The 412nd, fiber drawing furnace; The 414th, the external diameter detecting device; The 416th, the coiling means; The 420th, shell; The 422nd, the stove core barrel; The 424th, well heater; The 426th, mother metal; The 427th, necking down (neckdown); The 428th, top cylinder; The 429th, arrow; The 430th, ring; The 432nd, the bottom cylinder; The 434th, switch; The 438th, plastic optical fiber

Embodiment

Plastic optical fiber of the present invention, such shown in the index distribution of Fig. 2, be fiber core part refractive index from core centre laterally, along radially successively decreasing, the refractive index of cladding part is lower than the plastic optical fiber of core centre, it is characterized in that, between above-mentioned fiber core part and above-mentioned cladding part, the part that refractive index is lower than above-mentioned cladding part refractive index is set.By the plastic optical fiber that design has such W type index distribution, reach the problem that solves higher mode.

Here core centre of the present invention is meant that a among Fig. 2 is a core centre in part inside of optical fibre, that radial refractive index is the highest.

Fiber core part of the present invention be meant from above-mentioned core centre (r0) laterally, the refractive index part with index distribution of radially successively decreasing; Among Fig. 2, b is a fiber core part.

Core periphery of the present invention is meant the most external of fiber core part, is r1 among Fig. 2.

Pars intermedia of the present invention is meant part between fiber core part and cladding part, that have the refractive index that is lower than cladding part.Usually, the refractive index of pars intermedia is identical with the refractive index of core periphery.But, even use the different plastics of plastics with the parent of fiber core part, when perhaps using the identical plastics of plastics with parent, the addition by changing additive (non-polymerization compound) that can refractive index variable etc. also can use and the peripheral different material of core.At this moment, the refractive index of pars intermedia also can be higher than the refractive index of core periphery, also can be lower than the refractive index of core periphery.But even in such cases, the refractive index of pars intermedia must be lower than the refractive index of cladding part.Pars intermedia exist or do not exist can, but preferably have pars intermedia.Among Fig. 2, c is a pars intermedia.

Cladding part of the present invention is meant the outside, the light transmission zone that covers optical fiber central authorities, the i.e. part of fiber core part and pars intermedia that is positioned at fiber core part (pars intermedia when having pars intermedia).The refractive index of cladding part is lower than the refractive index of core centre, and is higher than the refractive index of pars intermedia.D is a cladding part among Fig. 2.But the refractive index homogeneous of cladding part also can heterogeneity.

Here, the refractive index of optical fiber will have certain minimum value and the pattern that always changing is called " ditch ".When pars intermedia existed or do not exist, all there be (optical fiber that will have such index distribution is called W type POF) in this ditch.Can be near the refractive index minimum value, form certain steady state value, have the situation of the Fig. 2 on base in ditch, also can be that refractive index is converted into increase rapidly at the intersection of minimum value, has the situation of the Fig. 4 on base hardly.Shape for the index distribution of ditch is unrestricted.Better be to begin refractive index till the cladding part, be not to be interrupted hastily to change, but gradually change from core periphery (being pars intermedia when having pars intermedia).

So long as have the POF of the index distribution of such W type, there is not other special restriction, be more preferably the POF of the refractive index distribution curve shown in (1) that has following formula;

Formula (1)

n (r) = n_{1} [1 - 2 ρΔ {(\frac{r}{R})}^{g}]^{\frac{1}{2}} - - 0 \leq r \leq R

In the above-mentioned formula (1), r represents to leave the distance radially of core centre.The above-mentioned fiber core part of n (r) expression r position and the refractive index of pars intermedia.n ₁The refractive index of expression core centre.

R represents the radius of fiber core part.R0 among Fig. 2 is the radius of fiber core part to the distance of r1, and r0 is the radius of pars intermedia to the distance of r2.Actual optical fiber, more flat than cylinder is most, so R is as shown in the formula the radius d of the minimum circumscribed circle of described expression fiber core part _MaxRadius d with maximum inscribed circle _MinAverage:

R＝(d _max+d _min)/2

Δ represents that specific refractivity is poor, Δ=(n ₁-n ₂)/n ₁n ₂The refractive index of expression cladding part.

G represents refractive index profile coefficient, is the parameter of shape that influences the refractive index curve of fiber core part.During g=1, the refractive index of core centre is to the refractive index straight line of fiber core part external diameter descend (it is 1 situation that Fig. 3 chats ρ after being).Along with g greater than 1, the curvature of curve increases.Desirable g value among the present invention is 1.0-5.0, is more preferably 1.8-3.0, preferably 2.4.

ρ is as shown in the formula described expression pars intermedia specific refractivity.

ρ＝(n ₁-n ₃)/(n ₁-n ₂)

ρ=1 o'clock forms the GI type POF that does not have pars intermedia (ditch) fully, ρ=2 o'clock, the refractive index n of core periphery ₃Refractive index n with cladding part ₂Poor n ₂-n ₃, with the refractive index n of core centre ₁Refractive index n with cladding part ₂Poor n ₁-n ₂Identical (Fig. 4).The value of ρ among the present invention is greater than 1, smaller or equal to 2.Be more preferably 1.2-1.8.

POF with refractive index distribution curve of the present invention, as long as can form the index distribution of W type, its used polymkeric substance there is not any restriction, viewpoint from glass temperature and low transmission loss, better use at least a above polymkeric substance that contains in the fluoropolymer that is selected from acrylic polymers, polystyrene, polynorbornene, polycarbonate, polyimide and polyester and does not have hydrogen atom in fact, these polymkeric substance are used as the polymkeric substance that parent is used.Under the situation of acrylic polymers, better use and be selected from polymethacrylate, poly-methyl methacrylate base ester, methyl methacrylate-methacrylic acid benzyl ester co-polymer, all or part of hydrogen atom is replaced into polymethacrylate that D atom forms, all or part ofly hydrogen atom is replaced into poly-methyl methacrylate base ester that D atom forms, part hydrogen atom is replaced into polymkeric substance in the polymethacrylate of fluorine atom and the poly-methyl methacrylate base ester that part is replaced into hydrogen atom fluorine atom.As part hydrogen atom is replaced into the acrylic polymers of fluorine atom, available employing is polymkeric substance of making as monomer of the methacrylic acid trifluoroethyl ester (3FMA) shown in the following formula, perfluoroalkyl acrylate hexafluoro isopropyl fluoride ester (2FA-HFIP) etc. for example:

The better weight-average molecular weight (Mw) of these polymkeric substance is 40000-200000, is more preferably 60000-100000.When molecular weight is too small, hinder thermotolerance; If when excessive, very difficult formation has the optical fiber of index distribution.The matter average molecular weight is to be scaled the value that styrene is obtained by gel permeation chromatography (GPC).Below, mean molecular weight is meant the value of obtaining by this method.

During the situation of fluoropolymer,, it there is not any restriction so long as do not have noncrystalline fluoropolymer of hydrogen atom in fact." not having hydrogen atom in fact " and refer to so long as the terminal groups of polymkeric substance has the degree of hydrogen atom, substantially is synonym with not having hydrogen atom, does not consider to have hydrogen atom on the part that constitutes repetitive.As the fluoropolymer that does not have hydrogen atom, better with fluoropolymer with ring structure.Fluorochemicals with ring structure better is the fluorine-containing polycyclic compound that has carbocyclic ring more than 3 or 3 or heterocycle and do not have hydrogen atom in fact.

As fluoropolymer with ring structure, comprise the situation that the situation that has the ring structure on the main chain and side chain have ring structure, no matter any situation all can be used as matrix polymer, but preferably main chain has the fluoropolymer of ring structure.When side chain has ring structure situation, can enumerate the polystyrene etc. that hydrogen atom is replaced into fluorine atom, so that it does not substantially have hydrogen atom.

The fluoropolymer that has the ring structure on the main chain better is the fluoropolymer with fluorine-containing aliphatics ring structure, fluorine-containing imide ring structure, fluorine-containing triazine ring structure or fluorinated aromatic ring structure.Be more preferably fluoropolymer, promptly have the polymkeric substance of fluorine-containing aliphatics ether ring structure with fluorine-containing aliphatics ring structure.

Polymkeric substance with fluorine-containing aliphatics ring structure, concrete being fit to, will have the polymkeric substance that the monomer (at the carbon atom that constitutes ring and do not constitute have the monomer of the two keys of polymerism between the carbon atom of ring or constitute the monomer that has the two keys of polymerism between 2 carbon atoms of ring) of fluorine-containing ring structure is polymerized with (1); (2) fluorochemical monomer that will have two keys of polymerism more than 2 or 2 carries out having on the main chain that cyclopolymerization forms the polymkeric substance of fluorine-containing alicyclic ring structure.

Above-mentioned monomer with fluorine-containing alicyclic ring structure better is the monomer with the two keys of 1 polymerism, and the fluorochemical monomer that can carry out above-mentioned cyclopolymerization better is the monomer that has the two keys of 2 polymerisms and do not have fluorine-containing alicyclic ring structure.

Below, can be called " other free radical polymerization monomer " with the co-polymerized monomer that the monomer with fluorine-containing alicyclic ring structure carries out beyond the fluorochemical monomer of cyclopolymerization.

The carbon atom of formation fluoropolymer main chain is made of 2 carbon atoms of the two keys of polymerism of monomer.Therefore, in the monomer with the fluorine-containing alicyclic ring structure of having of the two keys of 1 polymerism, constituting in 2 carbon atoms of the two keys of polymerism 1 or 2 carbon atom all becomes the atom that constitutes alicyclic ring.Do not have alicyclic ring and have the fluorochemical monomer of the two keys of 2 polymerisms, 1 carbon atom of 1 carbon atom of the two keys of polymerism and the two keys of another polymerism combines and forms ring.Form alicyclic ring by 2 carbon atoms after the combination and atom therebetween (beyond the atom on the side chain), when between the two keys of 2 polymerisms, having etheric oxygen atom, can form fluorine-containing aliphatics ether ring structure.

To have the polymkeric substance that has fluorine-containing alicyclic ring structure on the main chain that the monomer polymerization of fluorine-containing alicyclic ring structure makes can form by the monomer polymerization that will have following fluorine-containing alicyclic ring structure: perfluor (2,2-dimethyl-1, the 3-dioxole) (abbreviates PDD as), perfluor (2-methyl isophthalic acid, the 3-dioxole), perfluor (2-ethyl-2-propyl group-1, the 3-dioxole), perfluor (2,2-dimethyl-4-methyl isophthalic acid, the 3-dioxole) has fluorine on etc. the dioxole ring carbon, trifluoromethyl, pentafluoroethyl group, the complete five fluorine dioxole classes of the fluorine substituted alkyl of seven fluoropropyls etc., perfluor (4-methyl-2-methylene-1, the 3-dioxolanes) (abbreviates MMD as), perfluor (2-methyl isophthalic acid, 4-dioxolanes) etc.

Also available in addition will have the polymkeric substance of fluorine-containing alicyclic ring structure on this monomer and other the prepared main chain of free radical polymerization monomer copolymerization that does not contain hydrogen atom in fact.If during the increasing proportion of the polymerized unit of other free radical polymerization monomer, because fluoropolymer may descend to the transmitance of light, so better with the independent polymkeric substance of the monomer with fluorine-containing alicyclic ring structure, perhaps the ratio of the polymerized unit of monomer whose is more than or equal to the multipolymer of 70 moles of % for fluoropolymer.

As other the free radical polymerization monomer that does not contain hydrogen atom in fact, available tetrafluoroethene, chlorotrifluoroethylene, perfluor (ethylene methacrylic ether) etc.

The amorphous fluoropolymer of selling on the market that does not have hydrogen atom in fact as such type, available above-mentioned perfluor (2,2-dimethyl-1, the 3-dioxole) base polymer (trade name テ Off ロ Application AF: デユ Port Application company makes), perfluor (4-methoxyl-1,3-dioxole) base polymer (trade name HYFLONAD: アウジモ Application ト company makes) etc.

It is open by open the clear 63-238115 of communique number of Japan's special permission open clear 63-238111 of communique number and Japan's special permission etc. that the fluorochemical monomer that will have the two keys of polymerism more than 2 or 2 carries out cyclopolymerization makes, main chain has fluorine-containing aliphatics ring structure polymkeric substance.Promptly, by with perfluor (3-oxa--1, the 5-hexadiene), perfluor (3-oxa--1, the 6-heptadiene) the monomer cyclopolymerization that (abbreviates PBVE as) etc., perhaps, obtain the polymkeric substance that main chain has fluorine-containing alicyclic ring structure by other the free radical polymerization monomer copolymerization that does not contain hydrogen atom with above-mentioned monomer and tetrafluoroethene, chlorotrifluoroethylene, perfluor (ethylene methacrylic ether) etc.In the cyclopolymerization of above-mentioned PBVE,, form the polymerized unit that the main chain shown in the above-mentioned formula (I) has 5 yuan of cyclic ethers keys by the combination of 2,6 carbon.

As fluorochemical monomer with the two keys of polymerism more than 2 or 2, except that above-mentioned, also available for example have a substituent monomer on the saturated carbon of PBVE, specifically, more handy perfluor (4-methyl-3-oxa--1,6-heptadiene) (abbreviating PBVE-4M as), perfluor (4-chloro-3-oxa--1,6-heptadiene) (abbreviating PBVE-4Cl as), perfluor (5-methoxyl-3-oxa--1, the 6-heptadiene) (abbreviate PBVE-5MO as), perfluor (5-methyl-3-oxa--1,6-heptadiene) etc.If the increasing proportion of the polymerized unit of other free radical polymerization monomer, fluoropolymer can descend to the transmitance of light, so fluoropolymer is better with the ratio of the polymerized unit of the independent polymkeric substance of the fluorochemical monomer with the two keys of polymerism more than 2 or 2 or the monomer whose co-polymer more than or equal to 40 moles of %.

As such commodity that do not have amorphous fluoropolymer of hydrogen atom in fact, be " サイト Star プ " (Asahi Glass company trade name).

Even make perfluor (2,2-dimethyl-1, the 3-dioxole) etc. monomer and perfluor (3-oxa--1 with fluorine-containing alicyclic ring structure, the 5-hexadiene), perfluor (3-oxa--1, the 6-heptadiene) the fluorochemical monomer copolymerization with the two keys of polymerism more than 2 or 2 that (PBVE) waits also can obtain the fluoropolymer that main chain has fluorine-containing alicyclic ring structure.At this moment, owing to the transmitance of light being descended, so better be to have the ratio of polymerized unit of fluorochemical monomer of the two keys of polymerism more than 2 or 2 more than or equal to the multipolymer of 30 moles of % through combination.

Polymkeric substance with fluorine-containing alicyclic ring structure better is the polymkeric substance that main chain has the ring structure, but from aspects such as the transparency, mechanical properties, better use and contain with respect to whole polymerized units, polymerized unit with ring structure is more than or equal to 20 moles of %, better more than or equal to the multipolymer of 40 moles of %.

Polymkeric substance with fluorine-containing alicyclic ring structure better is a (per) fluoropolymer.That is, better be the polymkeric substance that whole hydrogen atoms of combining with carbon atom are substituted by fluorine atom.But the fluorine atom of the part of (per) fluoropolymer also can be replaced by the atom beyond the hydrogen atoms such as chlorine atom, D atom.The existence of chlorine atom has the effect of the refractive index that improves polymkeric substance.

Fluoropolymer with above-mentioned fluorine-containing alicyclic ring structure, with have after the fluoropolymer of fluorine-containing imide ring structure, fluorine-containing triazine ring structure or the fluorinated aromatic ring structure chatted compare, even utilize hot-stretch or melt spinning to carry out fiberization processing, polymer molecule also is difficult to orientation, so be difficult to cause light scattering etc., because these reasons are special good.Fluoropolymer spy with fluorine-containing aliphatics ether ring structure is good.

As above-mentioned polymkeric substance with fluorine-containing alicyclic ring structure, specifically, available have a polymkeric substance that is selected from following (I)-(V) repetitive shown in the formula.The fluorine atom that these have in the polymkeric substance of fluorine-containing alicyclic ring structure in order to improve refractive index, also can be replaced by the chlorine atom of a part.In addition, the multipolymer more than 2 kinds or 2 kinds in also available (I)-(V) formula,

In above-mentioned (I)-(V) formula, 1 expression 0-5; M represents 0-4; N represents 0-1; But 1+m+n is 1-6; O, p and q are independent separately, expression 0-5, and o+p+q is 1-6; R ¹Expression F or CF ₃R ¹-R ⁴, X ¹And X ²Independent separately, expression F, Cl, CF ₃Or OCF ₃

The more handy main chain of polymkeric substance that contains fluorine-containing aliphatics ring structure has the polymkeric substance of ring structure, from aspects such as the transparency, mechanical properties, the more handy polymerized unit with ring structure of containing is more than or equal to 20 moles of %, better more than or equal to the polymkeric substance of 40 moles of %.

Above-mentioned main chain has the fluoropolymer of fluorine-containing alicyclic ring structure, and is one of the matrix polymer of the best of the present invention, as such as mentioned above matrix polymer, unrestricted to this.As fluoropolymer, can also more handy main chain has the fluoropolymer of fluorine-containing imide ring structure etc.Specifically, available polymkeric substance with the repetitive shown in the following general formula;

R in the formula ¹Be selected from following group,

R ²Be selected from following group,

Here, R _fBe selected from fluorine atom, perfluoroalkyl, perfluor aryl, perfluoro alkoxy, perfluor phenoxy group, these groups can be identical, also can be different.Y is selected from following group;

-O-，-CO-，-SO ₂-，-S-，-R _f′-，

-(OR _f′) _r-，-(R _f′O) _r-，-(OR _f′O) _r-，

-(SR _f′) _r-，-(R _f′S) _r-，-(SR _f′S) _r-，

-(SR _f′O) _r-，-(OR _f′S) _r-

The R here _f' being selected from perfluoroalkyl, perfluor aryl, these can be identical separately, also can be different.R is 1-10.Y and 2 R _fCan accompany carbon and form ring, at this moment, ring can be a saturated rings, also can be unsaturated ring.

In the present invention, as the fluoropolymer that contains fluorinated aromatic ring structure, the fluorine that side chain such as available polystyrene, polycarbonate, polyester or main chain have aromatic polymkeric substance replaces body.These can be the perfluor bodies after perfluor replaces, and can be to replace the material that the remnants of defeated troops form with replacement fluorine such as chlorine.In addition, also can have methenyl choloride substituting group etc.

Fluorine atom in the above-mentioned fluoropolymer in order to improve refractive index, also can be replaced by the chlorine atom of a part.Can also in fluoropolymer, contain the material that improves refractive index.

Above-mentioned fluoropolymer preferably has enough molecular weight, even so that optical transmit body has thermotolerance at high temperature, also is difficult to softening and does not reduce transmission performance to light.Molecular weight for the fluoropolymer that shows above-mentioned characteristic, the molecular weight that is shaped with melting is as the upper limit, but 30 ℃ of perfluors (butyl tetrahydrofuran) (PBTHF) in measured intrinsic viscosity " η ", better be about 0.1-1dl/g usually, better be about 0.2-0.5dl/g.The number-average molecular weight suitable with this intrinsic viscosity is about 1 * 10 usually ⁴-5 * 10 ⁶, better be about 5 * 10 ⁴-1 * 10 ⁶

In order to ensure with above-mentioned fluoropolymer melt spinning the time, the formability the during stretch process that perhaps is shaped in advance, the melt viscosity of the fluoropolymer of 200-300 ℃ of molten fluoropolymer better is about 1 * 10 ²-1 * 10 ⁵Pas.

Below put down in writing the best of breed that constitutes the polymkeric substance of fiber core part, pars intermedia and cladding part, but unrestricted to this.

(1) combination-1

Fiber core part contains poly-methyl methacrylate base ester at least; Pars intermedia contains poly-methyl methacrylate base ester at least, and cladding part contains methyl methacrylate-methacrylic acid benzyl ester multipolymer and the plastic optical fiber that forms at least.

(2) combination-2

Fiber core part contains hydrogen atom at least and is all replaced the poly-methyl methacrylate base ester that forms by D atom; Pars intermedia contains hydrogen atom at least and is all replaced the poly-methyl methacrylate base ester that forms by D atom, and cladding part contains poly-methyl methacrylate base ester and the plastic optical fiber that forms.

As mentioned above the hydrogen atom heavy-hydrogenated can be realized the low transmission loss in the light time of transmission as the 0.6-0.9 μ m of signal wavelength, form better POF material.

(3) combination-3

Fiber core part contains the polymkeric substance with the fluorine-containing aliphatics ring structure that is selected from above-mentioned (I)-(V) formula at least; Pars intermedia contains at least and is lower than the polymkeric substance that having of fiber core part refractive index is selected from the fluorine-containing aliphatics ring structure in above-mentioned (I)-(V) formula, and cladding part contain the refractive index ratio core centre low and be selected from the polymkeric substance of the fluorine-containing aliphatics ring structure in above-mentioned (I)-(V) formula and the plastic optical fiber that forms than high the having of pars intermedia.

Contain the fluorine-containing aliphatics ring structure that is selected from above-mentioned (I)-(V) formula as mentioned above, the same with the situation of heavy-hydrogenated, in the light time of transmission, realize the low transmission loss as the 0.5-1.55 μ m of signal wavelength, form better POF material.

More handy aforesaid polymkeric substance is as parent, but the polymkeric substance that the parent of fiber core part, pars intermedia and cladding part is used can be different separately polymkeric substance, also can be identical polymkeric substance.But for the refractive index of the fiber core part, pars intermedia and the cladding part that make W type POF different, when using same polymer, add the compound (the non-polymerization compound that for example the following describes etc.) that can change refractive index, monomer more than 2 kinds or 2 kinds is formed multipolymer etc. as raw material, need handle.

The non-polymerization compound, be difference with the refractive index of matrix polymer more than or equal at least a material in 0.001 the material, can be than the refractive index height of matrix polymer, can be lower than the refractive index of matrix polymer.Usually use the material of the refractive index that is higher than matrix polymer.In addition, the non-polymerization compound does not preferably have reactive compound to this polymkeric substance.The non-polymerization compound can use a kind separately, also material more than 2 kinds or 2 kinds can be share.

Especially the fiber core part in the optical fiber of the present invention, from the core centre to the outside, has the index distribution of radially successively decreasing, as the method that forms such index distribution, the available concentration gradient that diffuses to form by the non-polymerization compound, the method for formation index distribution.

Except fiber core part,, also to add the processing of non-polymerization compound to cladding part, pars intermedia in order to adjust refractive index.

When matrix polymer was the polymkeric substance that is selected from more than at least a or at least a in acrylic polymers, polystyrene, polynorbornene, polycarbonate, polyimide, polyester, polycarbonate and the polyester, the non-polymerization compound better was at least a or at least a above compound that is selected from diphenyl sulfide, Ergol, diphenyl sulfoxide, triphenyl phosphate, phthalic acid dibutyl ester and the tricresyl phosphate.The spy is a diphenyl sulfide well.These non-polymerization compounds, along with concentration increases, refractive index also increases.

Matrix polymer is when not having the fluoropolymer of hydrogen atom in fact, and the non-polymerization compound better is to contain low molecular compound, oligomer, the polymkeric substance in conjunction with base such as halogen atoms such as aromatic ring, chlorine, bromine, iodine, ehter bond such as phenyl ring.The non-polymerization compound better is the material that does not have hydrogen atom in fact.With the difference of the refractive index of matrix polymer better more than or equal to 0.005.

Be the non-polymerization compound of oligomer or polymkeric substance, better constitute by the aforesaid polymer of monomers that forms fluoropolymer, with the difference of the refractive index of matrix polymer better more than or equal to 0.001.2 kinds of fluoropolymers that such non-polymerization compound is different with the available for example refractive index of the combination of matrix polymer, a kind of fluoropolymer wherein can be used as the non-polymerization compound.

These non-polymerization compounds, the difference of the solubility parameter that compares with above-mentioned parent is 7 (cal/cm more fortunately ³) ^1/2In.The solubility parameter here is the characteristic value as the Combination yardstick between material, and establishing solubility parameter is δ, and the molecule inner injection of material can be E, and molar volume is V, can be by formula δ=(E/V) ^1/2Expression.

The non-polymerization compound of low molecular compound is not contain the halogenated aromatic that is combined in the hydrogen atom on the carbon atom.Especially only contain fluorine atom as the halogenated aromatic of halogen atom or contain fluorine atom and the halogenated aromatic of other halogen atom, from the aspect of the intermiscibility of fluoropolymer, comparatively desirable.It is even more ideal that these halogenated aromatic do not have functional groups such as carbonyl, cyano group.

Such halogenated aromatic can be enumerated as: (φ r is that the b valency after whole hydrogen atoms is replaced by fluorine atom is fluoridized the aromatic rings residue to formula φ r-Zb, Z be beyond the fluorine halogen atom ,-Rf ,-CO-Rf ,-O-Rf or-CN, and Rf is the φ r of perfluoroalkyl, polyfluoro perfluoroalkyl or 1 valency; B is the integer more than 0 or 1) shown in compound.But aromatic rings phenyl ring or naphthalene nucleus.As the carbon number of the perfluoroalkyl of Rf or polyfluoro perfluoroalkyl more fortunately below 5.Halogen atom beyond the fluorine better is chlorine atom and bromine atoms.

Concrete compound can be enumerated as: 1,3-dibromo phenyl tetrafluoride, 1,4-dibromo phenyl tetrafluoride, 2-bromine phenyl tetrafluoride trifluoride, chlorine phenyl-pentafluoride, bromine phenyl-pentafluoride, iodine phenyl-pentafluoride, ten fluorine benzophenone, perfluor acetophenone, perfluorinated biphenyl, chlorine seven fluoronaphthalenes, bromine seven fluoronaphthalenes etc.

The non-polymerization compound that is polymkeric substance or oligomer better is fluoropolymer repetitive, that have the refractive index that is different from the fluoropolymer that is made up with above-mentioned (I)-(V) (for example will only contain the fluoropolymer and the fluoropolymer combination that contain fluorine atom and chlorine atom of fluorine atom as halogen atom, the combination of 2 kinds of fluoropolymers that 2 above monomer polymerizations of variety classes and different proportion are formed etc.).

On above-mentioned main chain, have the fluoropolymer of ring structure, the oligomer that also can use tetrafluoroethene, chlorotrifluoroethylene, dichloro difluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether etc. to be made of the monomer that does not contain hydrogen atom, oligomer that the above-mentioned monomer copolymerization more than 2 kinds is formed etc. is as the non-polymerization compound.Also can use and have-CF ₂CF (CF ₃) O-or-(CF ₂) _nThe PFPE of the structural unit of O-(n is the integer of 1-3) etc.The molecular weight of these oligomer is selected from the scope that forms noncrystalline molecular weight, and number-average molecular weight is preferably 300-10000.If consider the easy degree of diffusion, number-average molecular weight is more preferably 300-5000.

One of non-polymerization compound preferred example is the chlorotrifluoroethylene oligomer, this be from fluoropolymer, particularly with main chain on have a ring structure fluoropolymer have and consider on the good intermiscibility.Because intermiscibility is good, thus can be at 200-300 ℃ of following heating and melting easily with fluoropolymer, and the fluoropolymer that particularly has the ring structure on the main chain mixes with the chlorotrifluoroethylene oligomer.In addition, make its be dissolved in contain in the fluorous solvent mix after, removing desolvates can mix both equably.Chlorotrifluoroethylene oligomer optimum weight is number-average molecular weight 500-1500.

The concrete example of special good non-polymerization compound is: be selected from the fluorine-containing polycyclic compound (B) more than a kind in following (B1)-(B3).

(B1) with carbocyclic ring or heterocycle and have fluorine atom or more than 2 of the fluorine-containing ring of perfluoroalkyl, carry out the fluorine-containing non-condensed polycyclic compound that bonding forms to contain more than one the key that is selected from triazine ring, oxygen atom, sulphur atom, phosphorus atoms and metallic atom, and do not have hydrogen atom in fact.

(B2) with carbocyclic ring or heterocycle and have fluorine atom or more than 3 of the fluorine-containing ring of perfluoroalkyl, with directly or the key that contains carbon atom carry out the fluorine-containing non-condensed polycyclic compound that bonding forms, and do not have hydrogen atom in fact.

(B3) be the fused polycyclic compound that constitutes by carbocyclic ring more than 3 or heterocycle, and be the fluorine-containing fused polycyclic compound that does not have hydrogen atom in fact.

Above-mentioned fluorine-containing polycyclic compound is the compound that does not have the caused c h bond of near-infrared region light absorption (that is carbon-hydrogen link) in fact.Above-mentioned fluorine-containing polycyclic compound better is to have hydrogen atoms whole in the compound by the perfluorochemical of the structure of fluorine atom or perfluoroalkyl replacement.In the scope that does not influence purpose of the present invention, the fluorine atom of the part in this perfluorochemical also can be replaced by 1-2 chlorine atom or bromine atoms.The number-average molecular weight of fluorine-containing polycyclic compound (B) is preferably 3 * 10 ²-2 * 10 ³, more preferably 3 * 10 ²-1 * 10 ³From the deliquescent viewpoint of raising with the noncrystalline fluoropolymer that does not have hydrogen atom in fact of matrix polymer, better has perfluoroalkyl in the fluorine-containing polycyclic compound (B), have the viewpoint of big refringence from refractive index, better do not have perfluoroalkyl in the fluorine-containing polycyclic compound (B) with matrix polymer.

Fluorine-containing polycyclic compound (B) better is carbocyclic ring or the heterocycle with fluorine atom or perfluoroalkyl.Carbocyclic ring and heterocycle better are selected from 4 yuan more than the ring, better are selected from 4-6 unit ring.The atom that constitutes heterocycle better is carbon atom, nitrogen-atoms, oxygen atom, sulphur atom and phosphorus atoms etc.Perfluoroalkyl better is that carbon number is the perfluoroalkyl of 1-20.

Carbocyclic ring is: the ring type stable hydrocarbon ring of cyclopentane ring, cyclohexane ring etc.; 1 or 2 aromatic hydrocarbon ring such as ring that formed by methyl substituted of the hydrogen atom of phenyl ring, phenyl ring; Ring type unsaturated hydrocarbon ring beyond the aromatic hydrocarbon rings such as cyclopentene ring, cyclohexene ring etc.Heterocycle can be that the heteroatoms of thiphene ring, furan nucleus, pyridine ring, triazine ring, triazole ring etc. is a kind a heterocycle; The heteroatoms of isothiazole etc. is 2 kinds a heterocycle etc.Fluorine-containing preferably ring is fluorine-containing aromatic hydrocarbon ring, and better fluorine-containing ring is the perfluor aromatic hydrocarbon ring, and aromatic hydrocarbon ring better is a phenyl ring.

Fluorine-containing polycyclic compound (B) is the compound that the fluorine-containing ring more than 2 or 3 does not have the atom be combined into more than 2.The combination that does not have the atom more than 2 and carry out is meant that fluorine-containing ring has 1 atom and carries out combination, and perhaps fluorine-containing ring carries out directly combination or combination indirectly.Fluorine-containing ring carries out indirectly in conjunction with being meant that the atom that fluorine-containing ring accompanies more than 1 or 1 carries out combination.

2 fluorine-containing rings carry out in conjunction with the time, this key is to comprise the key more than a kind that is selected from triazine ring, oxygen atom, sulphur atom, phosphorus atoms and metallic atom.More than 3 fluorine-containing ring carry out in conjunction with the time, this key is the key more than a kind that is selected from triazine ring, oxygen atom, sulphur atom, phosphorus atoms and metallic atom, is the direct key more than 3 of fluorine-containing ring or the key that comprises carbon atom.

The more handy metallic atom that is selected from the 2-4 valency among Zn, Sn, Pb, Ge, Si, Ti, Hg, Tl, As, Se, Te and the Cd of metallic atom.From giving fluorine-containing non-condensed polycyclic compound good thermal stability and chemical stability, metallic atom better is the Sn atom.

It better is the fluorinated aromatic triaizine compounds of each expression in the following formula 1-formula 3 that fluorine-containing ring more than 2 closes the fluorine-containing non-condensed polycyclic compound that forms by the bond that contains triazine ring.In this manual, remove the residue of g fluorine atom in Φ g (g is the integer of 1-6) the expression perfluor benzene.When removing behind g the fluorine atom remaining fluorine atom, also can have this a part of fluorine atom or whole fluorine atoms is replaced the structure that forms by perfluoroalkyl.

The bond that fluorine-containing ring more than 2 is contained phosphorus atoms is closed the fluorine-containing non-condensed polycyclic compound that forms better to be the compound shown in (Φ 1) 3-P or to close the compound that forms with the bond that contains the ホス Off アザトリエ Application ring shown in the following formula 4.

With the key that contains sulphur atom the fluorine-containing loops more than 2 being closed the fluorine-containing non-condensed polycyclic compound that forms better is the fluorinated aromatic sulfocompound shown in following formula 5 or 6.H is the integer of 1-4 in the formula 5, and the k in the formula 6 is the integer of 1-6.

With the key that contains metallic atom the fluorine-containing loops more than 2 being closed the fluorine-containing non-condensed polycyclic compound that forms better is the fluorinated aromatic containing metal compound shown in following formula 7 or 8.M in the formula 7 and 8 is the metallic atom that is selected from Zn, Sn, Pb, Ge, Si, Ti, Hg, Tl, As, Se, Te and Cd, and p, q are the valence mumbers of metal M, is the integer of 2-4.

Fluorine-containing ring more than 3 by directly or the bond that contains carbon to close the fluorine-containing non-condensed polycyclic compound that forms better be the aromatic fluorine compound shown in each among the following formula 9-12.Never hinder the viewpoint of the transparency of refractivity distributing optical resin material and see, the sum of the number of the Φ 1-Φ 4 in the aromatic fluorine compound better is 3-5.

Formula 1 Formula 2

Formula 3 Formula 4

Formula 5

Φ ^k(s-Φ ¹) _kFormula 6

Formula 7

Formula 8

(r is the integer of 3-7) formula 9

Formula 10

Formula 11

Formula 12

The fused polycyclic compound that constitutes by carbocyclic ring more than 3 or heterocycle and part or all hydrogen atom by fluorine atom or the carbocyclic ring of the fluorine-containing fused polycyclic compound after containing fluorine-based replacement and heterocycle better be 4 yuan of rings more than the ring, be more preferably the ring of 4-6 unit.The best atom that constitutes heterocycle can be selected from carbon atom, nitrogen-atoms, oxygen atom, sulphur atom and phosphorus atoms etc.

As fluorine-containing fused polycyclic compound, fluorine-containing condensation polycyclic formula hydrocarbon that non-which alkene (Off エ Na レ Application) of more handy perfluor fluorenes, perfluor, Decafluorophenanthrene (phenanthrene), perfluor anthracene, perfluor benzo (9,10) phenanthrene, perfluor pyrene, perfluor (chrysene) in the wrong, perfluor aphthacene etc. are made of 3-4 carbocyclic ring or the fluorine-containing fused polycyclic compound shown in following formula 13 or the formula 14;

Formula 13

Formula 14

Never hinder the viewpoint of the POF transparency and see, better use the fluorine-containing condensation polycyclic formula hydrocarbon that constitutes by 3 carbocyclic rings of non-any alkene (Off エ Na レ Application) of perfluor fluorenes, perfluor, Decafluorophenanthrene (phenanthrene), perfluor anthracene etc.

Fluorine-containing polycyclic compound (B) better be selected from Heat stability is good, with high compound of the dissolubility of matrix polymer and the compound that does not hinder the transparency of refractivity distributing optical resin material.As so fluorine-containing polycyclic compound (B), special handy fluorine-containing ring more than 2 closes the fluorine-containing non-condensed polycyclic compound that forms with the bond that contains triazine ring at least.As triazine ring, available 1,2,3-triazine ring, 1,2,4-triazine ring and 1,3,5-triazines ring, special handy 1,3,5-triazines ring.

The addition of non-polymerization compound can be according to the kind of polymkeric substance that forms parent and non-polymerization compound different and different.But, if not when the addition of polymerizable compound was too much, low molecule existed in a large number, can produce the thermotolerance problem, thus, with respect to having the refractive index matrix polymer of the fiber core part of decline curve gradually, 5 quality %-20 quality % more fortunately.

Below, the method for the best of W type POF mother metal of the present invention is made in record, but is not limited thereto.

(1) interface gel polymerization method

In the interface gel polymerization method, used the cylinder container of hollow in the fibre parent material manufacturing, made its polymerization, so, around hollow tube, form gel layer in the polymerization initial stage by light and heat from the hollow tube outside.At this moment, the molecular dimension of above-mentioned non-polymeric compound is difficult to enter in the hollow tube gel layer on every side greater than monomer.Its result, along with constantly close to the center of not carrying out polyreaction, non-polymeric compound concentrations increases, and forms index distribution.

The interface gel polymerization method is used to form from core centre laterally, the fiber core part that descends gradually along radial refractive index, do not have special restriction for the cladding part beyond the fiber core part and the manufacture method of pars intermedia, but preferably have the manufacture method of the operation of following a-c at least:

(a) plastic raw materials that will form above-mentioned cladding part is injected in the cylinder container (for example glass tube) of hollow, on one side rotation, polymerization on one side forms the operation of the cladding part cylinder of hollow;

(b) plastic raw materials that will form above-mentioned pars intermedia is injected in the cladding part cylinder of hollow, on one side rotation, polymerization on one side forms the operation of the pars intermedia cylinder of hollow in the inboard of above-mentioned cladding part cylinder;

(c) plastic raw materials that will form above-mentioned fiber core part injects the pars intermedia cylinder of above-mentioned hollow, and polymerization forms the operation of above-mentioned fiber core part.

The plastic raw materials of the formation cladding part among the operation a is meant following raw material: except the monomer that contains the raw material that becomes above-mentioned parent usefulness polymkeric substance, can also contain above-mentioned non-polymeric compound, polymerization initiator and chain-transferring agent.In addition, becoming parent can be the monomer of same kind with the monomer of the raw material of polymkeric substance, also can be the monomer more than 2 kinds.When the monomer that adds more than 2 kinds, form multipolymer.

When the used monomer of the present invention carries out polyreaction, better use with the free radical polymerization as polymerization initiator such as superoxide with O-O key or azo compound.As such polymerization initiator, that be fit to use benzoyl peroxide, lauroyl peroxide, t-butylperoxide etc. effectively produces warm initiating agent in free radicals so-called being about 40 ℃-130 ℃.The temperature conditions that uses warm initiating agent in this to carry out polyreaction be about 40 ℃-120 ℃ comparatively suitable.Polymerization rate must be controlled so that in the polyreaction or reacted polymkeric substance can self expand to shrink not produce fracture etc. because of reaction heat and reaction, and reaction heat does not make monomer seethe with excitement in reaction.Can come adjusted by the combination of polymerization temperature and initiating agent addition.The addition of this initiating agent when being about 40 ℃-120 ℃, with respect to the amount of monomer, is about about 0.001-10 weight %, better is about 0.01-1.0 weight %.

Carry out in the polymerization at the aforesaid heat energy that utilizes, also can and carry out from the external container heating of the cylinder of hollow.Except utilizing heat energy to carry out to utilize luminous energy to carry out polymerization etc. the polymerization.With above-mentioned the same,, adjust polymerization rate by intakes such as temperature and concentration are made up.

Do not have special restriction for chain-transferring agent, can from known chain-transferring agent, suitably select.As above-mentioned known chain-transferring agent, aromatic hydrocarbon such as available benzene, cumene; Halogenide such as chloroform, phenixin; Thiol compounds such as the butyl mercaptan compound of SH base (have-); Alcohols such as methyl alcohol.

Hollow cylindrical body container among the operation a, as long as above-mentioned shape is arranged, what can, can use the container of various materials such as glass.But, because polymerization as described below is free radical reaction, so for the sneaking into of the airborne oxygen that prevents to hinder Raolical polymerizable, hollow cylindrical body better is the container that the container that can seal or the container of formation blanket of nitrogen gas etc. can stop oxygen to be sneaked into.

During rotation, rotation number is more fortunately below the 10000rpm, better at 100rpm-5000rpm.

The raw material of the plastics of the formation pars intermedia of operation b contains becomes the monomer of above-mentioned parent with the raw material of polymkeric substance, in addition, can also contain polymerization initiator, non-polymeric compound, chain-transferring agent.This monomer can be a single kind, also can be the kind more than 2 kinds.When adding the monomer more than 2 kinds, form multipolymer.

In the present invention, pars intermedia is the minimum part of refractive index in the inside of optical fibre, so also may contain the adjuvant that the refractive index that reduces this monomer is used.

In operation b, also the same with operation a, rotation number is more fortunately below the 10000rpm, better at 100rpm-5000rpm.

To form in the cladding part of prepared hollow among the raw material injection process a of plastics of pars intermedia, on one side can rotate the formation of polymerization on one side pars intermedia cylinder; Also can be with the raw material of the plastics that form pars intermedia, make it be aggregated to viscosity when being about 1000cps-7000cps in advance, inject the cylinder of hollow, rotate, further polymerization the pars intermedia cylinder of formation hollow on one side.

The plastic raw materials of the formation fiber core part of operation c contains the non-polymerization compound that can form index distribution with the monomer and the concentration gradient of the raw material of polymkeric substance as above-mentioned parent, in addition, can also contain polymerization initiator, non-polymeric compound, chain-transferring agent.This monomer can be a single kind, also can be the kind more than 2 kinds.When adding the monomer more than 2 kinds, form multipolymer.

In the pars intermedia of the hollow that the plastic raw materials injection process a that forms fiber core part is made, on one side rotation, polymerization on one side forms fiber core part; Also can use the plastic raw materials that forms fiber core part, and when it is polymerized to viscosity in advance and is about 1000cps-7000cps, inject in the cylinder of hollow, on one side rotation, further polymerization on one side forms fiber core part.

Operation c can carry out 1 stage, also can repeat the above fiber core part of making of 2 stages.Be more preferably, such according to the formula (1) of index distribution, divide the manufacturing of above adjustment of 2 stages refractive index to form.The adjustment of refractive index can be by changing the non-polymerization compound addition and kind etc. carry out.

In the manufacturing of fiber core part, needn't be aggregated to the above-mentioned optimum weight of core centre, also can finish polymerization midway.But,, better be aggregated to above-mentioned molecular weight as whole fiber core part.

The manufacture method of POF mother metal is better carried out according to the order of operation a, b, c preferably, begins from the outside of POF mother metal to form, form the fiber core part of core at last, but, also can begin to make its polymerization from the center by light and heat, form the footpath peripheral part at last.At this moment, the non-polymerization compound is the material that refractive index is lower than matrix polymer.Form gel layer by begin to be aggregated in the footpath central part from the center, the non-polymerization compound does not enter in the gel layer, so it is low to form the non-polymerization compound concentrations of footpath central part, and the concentration gradient that the non-polymerization compound concentrations of footpath periphery increases.

(2) DD method

In the DD method, make the starting monomer polymerization that does not contain the non-polymerization compound in advance, the core of making cylinder is the cylinder of hollow.The non-polymerization compound is injected this hollow space, rotate the cylinder make, on one side fusion on one side.The non-polymerization compound spreads laterally from the inboard in footpath, is radially forming non-polymerization compound concentrations gradient.Form POF mother metal like this with index distribution.Inject the non-polymerization compound, refer to that not only central part injects the situation of 1 layer non-polymerization compound, also refer to inject the non-polymerization compound in the central part multilayer.

During with DD manufactured W type POF, can be the method with following operation: the cylinder of hollow be made in (1) polymerization in advance; (2) empty therein part is injected the non-polymerization compound; (3) make the operation of cylinder fusion; Also can better use the method that has following a-d operation at least:

(a) make the polymerizable raw material of the plastics that form above-mentioned cladding part, form the operation of the cladding part cylinder of hollow;

(b) make the polymerizable raw material of the plastics that form above-mentioned pars intermedia, form the operation of the pars intermedia of hollow;

(c) hollow space of the above-mentioned pars intermedia that non-polymerization compound injection process b is made, the fusion pars intermedia, make the diffusion of non-polymerization compound, to form the part of index distribution by non-polymerization compound concentrations gradient, be that refractive index is higher than the high index of refraction part of cladding part as fiber core part, the low-refraction part that refractive index is lower than cladding part is made the operation of such cylinder as pars intermedia;

(d) hollow space of the above-mentioned cladding part that makes at operation a inserts the cylinder that operation c forms, and heats incorporate operation.

As operation d, the cylinder of the hollow that the cylinder insertion operation a that operation c is made in advance makes, the method for making the POF mother metal is post tubular stinger (rod-in-tube) method, makes the DD method of W type POF of the present invention and better makes by post tubular stinger method.

Also can make the POF mother metal: after above-mentioned operation (a) through following operation, the raw material that will form the plastics of above-mentioned pars intermedia through (b2) injects in the cladding part cylinder of above-mentioned hollow, the polymerization pars intermedia forms the operation of the pars intermedia cylinder of hollow in the inboard of above-mentioned cladding part cylinder; (c2) the non-polymerization compound is injected in the hollow space of pars intermedia of above-mentioned hollow, the fusion pars intermedia forms by the operation of non-polymerization compound concentrations gradient at the cylinder that radially forms index distribution.But, when using this manufacture method, must consider the glass temperature (Tg) of cladding part and pars intermedia, so the Tg of pars intermedia must be lower than the Tg of cladding part.This is because of easy fusion pars intermedia, and makes the diffusion of non-polymerization compound.When the Tg of pars intermedia was higher than the Tg of cladding part, in the fusion operation, cladding part and pars intermedia can mix, and are difficult to make the POF with W type refractive index.Select matrix polymer if consider Tg, even also can make W type POF with said method.

(3) dip coated

It is on the core that the matrix polymer that is made by melt spinning and stretching etc. constitutes, and repeated impregnations is coated with the non-polymerization compound or contains the method for the matrix polymer of this non-polymerization compound.

(4) utilize reactive difference of monomer

It is to adopt monomer that forms matrix polymer and the monomer that forms the non-polymerization compound, promptly adopt 2 kinds of reactive different monomers of these monomers, carry out polyreaction, so that the ratio of components of the repetitive of the repetitive of matrix polymer and non-polymerization compound carries out the continually varying method from periphery to the center.

(5) stripping is removed in volatilization

It is the potpourri that will matrix polymer and non-polymerization compound evenly be mixed or with above-mentioned after both evenly are blended in the solvent, the potpourri of only solvent evaporates being removed and making, carry out fiberization by hot-stretch or fusion extrusion, (after the perhaps firm fiberization) then, under heated condition, by it is contacted with inert gas, the non-polymerization compound is volatilized from the surface, form the method for index distribution.

It still is after the above-mentioned fiberization, not dissolve matrix polymer, and fiber impregnation in only dissolving non-polymerization compound solvent, by making the non-polymerization compound from the fiber surface stripping, is formed the method for index distribution.

(6) multilayer is extruded

It is at heating and melting or contain under the solution state of solvent and mix with high refractive index polymer and low refractive index polymer, extrude (perhaps extruding the back) with state one side multilayer of different blending ratios respectively, make both phase counterdiffusion on one side, finally make the method for the optical fiber that has formed index distribution.At this moment, high refractive index polymer can be a matrix polymer, and low refractive index polymer can be non-polymerizable compound; Perhaps high refractive index polymer can be a matrix polymer, and low refractive index polymer can be non-polymerizable compound.

The POF mother metal that will make is like this made optical fiber by stretching.The method that stretches, so long as normally used wire-drawing frame is unrestricted to this method, Fig. 5 has shown the summary that is suitable for wire-drawing frame of the present invention.Wire-drawing frame 410 is made of fiber drawing furnace 412, external diameter detecting device 414, coiling means 416.Fiber drawing furnace 412 has by metallic casing 420, be configured in top cylinder 428 and bottom cylinder 432 case formed of this shell about in the of 420 respectively.Fiber drawing furnace 412 contains above-mentioned case, be configured in the stove core barrel 422 of the pipe shape of above-mentioned case inside, be configured in the well heater 424 in the outside of this stove core barrel 422.

The wire-drawing frame 410 that utilization has an above-mentioned structure is during with the wire drawing of plastic optical fiber mother metal, and as shown in Figure 5, the plastic optical fiber mother metal 426 of drum is inserted into the inboard of stove core barrel 422, is configured in the fiber drawing furnace 412.Part wire drawing mother metal (that is, optical fiber 438) is reeled by coiling means 416, and fibre parent material 426 is left behind the necking part 427 that is generated by coiling, is configured in the fiber drawing furnace 412.

Plastic optical fiber mother metal 426 is not exclusively surrounded by shell 420 usually, and a part is outer to protrude in the top of top cylinder 428 and form residual state.In order to guarantee the impermeability of fiber drawing furnace 412, utilize to have and the external diameter of plastic optical fiber mother metal 426 ring 430 in the hole of size much at one, and with the last face seal of top cylinder 428.On the other hand, be equipped with metal switch 434 below the bottom cylinder 432, be provided with little opening near the center of this switch 434, so that wire drawing optical fiber passes through.

During wire drawing, well heater 424 heating of the plastic optical fiber mother metal 426 besieged stove core barrels 422 of stove core barrel 422 inside.For the oxidation on the surface of the plastic optical fiber mother metal 426 after preventing to heat and the inert gas that imports supply with in the fiber drawing furnace 412 by encircling 430, flow to stove core barrel 422 inside along arrow 429.Thus, pine in wire drawing adding of using, the mother metals 426 in the stove core barrel 422 are surrounded by the air-flow of inert gas.With the mother metal 426 of fixing speed spinning heating and melting, form plastic optical fiber 438, make its peristome that passes through above-mentioned switch 434, by external diameter detecting device 414, measure its external diameter after, rolled by coiling means 416.

The plastic optical fiber that makes as mentioned above can be used for optical cable.

Embodiment

Below, by embodiment and comparative example the present invention is specifically described.

(embodiment 1)

(making of W type POF-1)

In the glass tube of long 500mm, internal diameter 22mm, fill methyl methacrylate (abbreviating MMA as), the methacrylic acid benzyl ester (abbreviating Bz-MMA as) of 11g, caproic acid t-butyl peroxy-2-ethyl ester of 470 μ L, the 360 μ L normal-butyl mercaptan of 99g, after the sealing of upper end, the maintenance level, rotate with 3000rpm on one side, on one side 70 ℃ of heating 4 hours, stop the rotation thereafter, 90 ℃ of heating polymerization in 20 hours makes the cylindrical container by methyl methacrylate-methacrylic acid benzyl ester multipolymer constitutes.

With this end sealing by methyl methacrylate-cylindrical container that methacrylic acid benzyl ester multipolymer constitutes, fill MMA60g, caproic acid t-butyl peroxy-2-ethyl ester 300 μ L, 240 μ L butanethiols, after the sealing of upper end, the maintenance level, rotate with 3000rpm on one side, on one side 70 ℃ of heating 4 hours, stop the rotation thereafter, in 90 ℃ of heating polymerization in 20 hours, the inboard that makes methyl methacrylate-methacrylic acid benzyl ester multipolymer has the ducted body of poly-methyl methacrylate base ester (abbreviating PMMA as) layer.

Fill the diphenyl sulfide (abbreviating DPS as), two-t-butylperoxide of 12 μ L, the n-dodecyl mercaptan of 196 μ L of non-polymerization compound of methyl methacrylate, the 7.416g of 60g again in the inside of this ducted body, after its end sealing, in 90 ℃ of heating 24 hours, again at 110 ℃ heat also polymerization 48 hour, make the cylinder of external diameter 22mm thereafter.

This cylinder is vertically mounted in the cylinder feedway,, rolls melt spinning, make the optical fiber that diameter is 0.75mm with 220 ℃ cylindric heating furnace heating and melting and with the certain speed drawing.

The index distribution in the optical fiber cross section of the optical fiber that makes is measured the back to be found: as shown in Figure 6, after refractive index is successively decreased along the peripheral part direction from central division, obtain minimum refractive index, refractive index increases, and forms the POF of W type of the almost steady state value of the low-refraction that is lower than core centre in the outside.This refractive index curve is very consistent with following formula (1), g=2.2, ρ=2.

The long transport property of 100m that makes optical fiber has been carried out estimating the back to be found: the transmission loss during wavelength 650nm is 150dB/km, and transmission bandwidth is 2.12GHz, has and the equal superperformance of GI type POF that does not have ditch.

(making of W type POF-2)

In the glass tube of long 500mm, internal diameter 22mm, fill caproic acid t-butyl peroxy-2-ethyl ester, the 360 μ L normal-butyl mercaptan of MMA, the 470 μ L of 110g, after the sealing of upper end, the maintenance level, with the 3000rpm rotation,, stop the rotation thereafter on one side on one side 70 ℃ of heating 4 hours, 90 ℃ of 20 hours heated polymerizables make the cylindrical container that PMM constitutes.

End sealing with this PMMA container made, heavy-hydrogenated methyl methacrylate (abbreviating MMA (d8) as), caproic acid t-butyl peroxy-2-ethyl ester 300 μ L, 240 μ L butanethiols after the hydrogen atom of the methyl methacrylate of filling 60g is replaced by D atom, after the sealing of upper end, the maintenance level, rotate with 3000rpm on one side, on one side 70 ℃ of heating 4 hours, stop the rotation thereafter, 90 ℃ of 20 hours heated polymerizables, the inboard that makes the PMMA cylindrical container has the ducted body of heavy-hydrogenated poly-methyl methacrylate base ester layer.

Fill the two-t-butylperoxide, the n-dodecyl mercaptan of 196 μ L of DPS, 12 μ L of MMA (d8), the 7.416g of 60g again in the inside of this ducted body, after its end sealing, 90 ℃ were heated 24 hours, heated also polymerization 48 hours at 110 ℃ more thereafter, made the cylinder of external diameter 22mm.

The index distribution in the optical fiber cross section of the optical fiber that makes is measured the back to be found: with the POF of the same W of formation type of W type POF-1.This refractive index curve is very consistent with following formula (1), g=2.4, ρ=1.5.

The long transport property of 100m that makes optical fiber has been carried out estimating the back to be found: the transmission loss during wavelength 650nm is 85dB/km, and transmission bandwidth is 2.38GHz, is that transmission loss is than the little optical fiber of W type POF-1.

(making of no ditch GI type POF-1)

In the glass tube of long 500mm, internal diameter 22mm, fill caproic acid t-butyl peroxy-2-ethyl ester, the 600 μ L normal-butyl mercaptan of MMA, the 770 μ L of 170g, after the sealing of upper end, the maintenance level, with the 3000rpm rotation,, stop the rotation thereafter on one side on one side 70 ℃ of heating 4 hours, 90 ℃ of 20 hours heated polymerizables make the cylindrical container that is made of poly-methyl methacrylate base ester.

With the end sealing of this PMMA container made, fill MMA, the DPS of 7.416g of 60g, two-t-butylperoxide, 12 μ L, 196 μ L n-dodecyl mercaptans, after the sealing of upper end, 90 ℃ were heated 24 hours, heated also polymerization 48 hours at 110 ℃ again, made the cylinder that external diameter is 22mm.

The index distribution in the optical fiber cross section of the optical fiber that makes is measured the back to be found: be as shown in Figure 7, refractive index is successively decreased to the peripheral part direction from central division, forms the almost GI type POF of the refractive index of steady state value in its outside.

The long transport property of 100m that makes optical fiber has been carried out estimating the back to be found: the transmission loss during wavelength 650nm is 150dB/km, and transmission bandwidth is 1.8GHz.

(making of the GI type POF-2 of no ditch)

In the glass tube of long 500mm, internal diameter 22mm, fill caproic acid t-butyl peroxy-2-ethyl ester, the 600 μ L normal-butyl mercaptan of MMA (d8), the 770 μ L of 170g, after the sealing of upper end, the maintenance level, with the 3000rpm rotation,, stop the rotation thereafter on one side on one side 70 ℃ of heating 4 hours, 90 ℃ of 20 hours heated polymerizables make the cylindrical container that PMM constitutes.

End sealing with this PMMA container made, fill MMA (d8), the DPS of 7.416g of 60g, two-t-butylperoxide, 12 μ L, 196 μ L n-dodecyl mercaptans, after the sealing of upper end, the maintenance level, with 10rpm rotate on one side, on one side 95 ℃ of heating 24 hours, thereafter stop the rotation, 110 ℃ of heating polymerization in 48 hours makes the cylinder that external diameter is 22mm.

POF-1 is the same with the GI type, and refractive index is successively decreased to the peripheral part direction from central division, forms the almost GI type POF of the refractive index of steady state value in its outside.

The long transport property of 100m that makes optical fiber has been carried out estimating the back to be found: the transmission loss during wavelength 650nm is 80dB/km, and transmission bandwidth is 1.8GHz.

(evaluation)

1. the mensuration of mould dependence loss

The multimode incident illumination is mapped to the above-mentioned W type POF-1 that makes, 2 and the GI type POF-1 of no ditch on, measure the decay of each mould after 100m transmits.The loss of mould dependence is measured by the following method: by quartzy class single-mode fiber laser is incided on the GI type POF, the modular group that is confined to GI type POF is excited, measure the long dependence of optical fiber of outgoing intensity by reverse (cut back) method.Suitably the incoming position with single-mode fiber departs from from GI type POF center toward periphery, begins to excite respectively to the high order modular group from low order mode, calculates the transmission loss of each mould,

Fig. 8 has shown the comparison that the GI type POF-1 of PMMA class POF and W type POF-1 that ditch is arranged and no ditch is carried out.Among Fig. 8, transverse axis m/M is that the mould number of times is to whole moduluses.Transverse axis 0 is 0 apotype, and transverse axis 1 is higher mode.The figure that is equipped with triangle among Fig. 8 is the result of W type POF-1, and being equipped with circular figure is the result of the POF-1 of GI type.

As can be seen from Figure 8: exist the W type POF of ditch to compare with GI type POF, the decay in the higher mode is very little.

2. the mensuration of mould dependence time delay

Each modular group among above-mentioned W type POF-2 that makes and the no ditch GI type POF-2 is excited respectively, measure the time of arrival of each mould of 100m transmission back, measured arrival time delay with respect to 0 apotype.Mensuration is undertaken by Differential Mode Delay (DMD) method.DMD when the laser after the pulsed modulation is incided POF, carries out incident by quartzy class single-mode fiber, excites the modular group that is confined on the POF, is shaped as the basis with outgoing wave, measures the time delay of modular group by the position that excites that changes single-mode fiber.

Among Fig. 9, the longitudinal axis represents that time that 0 apotype is arrived is the arrival time delay of each mould of 0.The same m/M that represents with Fig. 8 of transverse axis, promptly the mould number of times is to whole moduluses.The figure of Fig. 9 is the result of following sample.

Black shape ... W type POF-2

Black circular ... GI type POF-2

As shown in Figure 9, exist the W type POF-2 of ditch to compare with the GI type POF-2 of no ditch, the delay of higher mode is few, is the few optical fiber of mould differentia influence.

(embodiment 2)

With the perfluor (3-oxa--1,6-heptadiene) (abbreviating PBVE as) of 20g, the perfluor (4-methyl-3-oxa--1,6-heptadiene) (abbreviating PBVE-4M as) of 20g, the ((CH of 500ml as polymerization initiator ₃) ₂CHOCOO) ₂Add in the glass tube, after the freezing degassing, Yi Bian high speed rotating, Yi Bian polymerization.From glass tube, take out the pipe of the hollow form after synthesizing, make number-average molecular weight and be about 1 * 10 ⁵The pipe of polymkeric substance system.

((CH with PBVE-4M, the 100ml of 10g as polymerization initiator ₃) ₂CHOCOO) ₂Add in the hollow bulb of this pipe, sealing, on one side low speed rotation, polymerization on one side makes the pipe with hollow.

With PBVE-4M, the 1g of 10g as the CTFE oligomer of non-polymerization compound, the ((CH of 100ml as polymerization initiator ₃) ₂CHOCOO) ₂Add in this hollow bulb, make its polymerization.

The CTFE oligomer

POF mother metal melt spinning with making as mentioned above makes the optical fiber that diameter is 0.75mm.The index distribution of this POF is: the refractive index of cladding part is 1.335, the minimum refractive index of pars intermedia is 1.328, the refractive index of core centre is 1.342, form the index distribution of above-mentioned W type, the same with embodiment 1, the light loss that forms higher mode is little, the plastic optical fiber that the light delay of higher mode is few.

(embodiment 3)

With the PBVE of 525g, the perfluor of 225g (4-chloro-3-oxa--1,6-heptadiene) (abbreviating PBVE-4Cl as), the ion exchange water of 4kg, the methyl alcohol of 260g and the ((CH of 3.7g ₃) ₂CHOCOO) ₂Put into the glass beaker of internal volume 5L.To after replacing in the system, 40 ℃ were carried out suspension polymerization 22 hours with nitrogen, and the number-average molecular weight that makes 690g is 5 * 10 ⁴Polymkeric substance.This polymkeric substance is carried out handling in 5 hours in fluorine/nitrogen mixture gas (fluorine gas concentration is 20 capacity %) atmosphere, under 250 ℃, can make the polymkeric substance (hereinafter referred to as polymer A 1) of photopermeability and Heat stability is good.

Polymer A 1 is put into the glass tube sealing, make the cylindrical duct that only constitutes by melt-shaping by polymer A 1.The refractive index of polymer A 1 is 1.35.

On the other hand, in the making of polymer A 1, replace using PBVE and the PBVE-4Cl all the other all identical polymer A 2 that make except using PBVE750g instead.

Polymer A 2 is put into the glass tube sealing, make the cylindrical duct that only constitutes by melt-shaping by polymer A 2.The refractive index of polymer A 2 is 1.342.

135-TPB is injected in these polymer A 2 cylindrical duct hollow bulbs, and 250 ℃ of melt-shapings make columned formed body (hereinafter referred to as formed body a).The refractive index of formed body a begins slowly to descend along periphery from the center, footpath;

135-TPB

Organizator a is inserted between the cylinder of polymer A 1 in the hollow bulb, 200 ℃ add heating integrated and make mother metal.230 ℃ with this mother metal melt spinning, make the optical fiber that diameter is 0.75mm.The index distribution of this POF is: the refractive index of cladding part is 1.35, the minimum refractive index of pars intermedia is 1.342, the refractive index of core centre is 1.358, form the index distribution of W type, with the embodiment 1 the same few plastic optical fiber of light loss light delay little, higher mode that forms higher mode.

(embodiment 4)

Except in embodiment 2, PBVE is changed to 3FMA, PBVE-4M is changed to 2FA-HFIP, the CTFE oligomer is changed to beyond the dibutyl phthalate, all the other all with identical method, make plastic optical fiber.

This POF index distribution is the index distribution of following W type: the refractive index of cladding part is 1.38, the refractive index of the minimum of pars intermedia is 1.36, the refractive index of core centre is 1.40.The same light loss that forms higher mode with embodiment 1 is little, the few plastic optical fiber of delay of the light of higher mode;

(embodiment 5)

Except in

embodiment

3,1,1,2 of the perfluor (2,2-dimethyl-1,3-dioxole) (abbreviating PDD as) of use 487.5g, 262.5g, 2-tetrafluoroethene (TFE) replaces PBVE and the PBVE-4Cl as the raw material of polymer A 1; Use the TFE of 637.5gPDD and 112.5g to replace raw material PBVE, in addition, make plastic optical fiber with the method the same with embodiment 3 as polymer A 2.

The glass temperature (Tg) of the polymer A 1 of this moment is 160 ℃, and the Tg of polymer A 2 is 240 ℃.

The POF index distribution is the index distribution of following W type: the refractive index of cladding part is 1.31, the minimum refractive index of pars intermedia is 1.29, the refractive index of core centre is 1.35.The loss of the same light that forms higher mode with embodiment 1 is little, the plastic optical fiber that the delay of the light of higher mode is few.

(embodiment 6)

In the glass tube of long 500mm, internal diameter 22mm, caproic acid t-butyl peroxy-2-ethyl ester, the 360 μ L normal-butyl mercaptan of DPS, the 470 μ L of MMA, the 5.5g of filling 104.5g, after the sealing of upper end, the maintenance level, with the 3000rpm rotation,, stop the rotation thereafter on one side on one side 70 ℃ of heating 4 hours, 90 ℃ of heating polymerization in 20 hours makes the cylindrical container that the DPS by PMMA and non-polymerization compound constitutes.

End sealing with this poly-methyl methacrylate base ester container made, fill caproic acid t-butyl peroxy-2-ethyl ester, the 240 μ L normal-butyl mercaptan of MMA, the 300 μ L of 60g, after the sealing of upper end, the maintenance level, with the 3000rpm rotation,, stop the rotation thereafter on one side on one side 70 ℃ of heating 4 hours, 90 ℃ of heating polymerization in 20 hours makes the ducted body that the cylindrical container inboard that is made of PMMA and DPS has the MMA layer.

In the inside of this ducted body, fill two-t-butylperoxide of DPS, the 12 μ L of MMA60g, 7.416g, the n-dodecyl mercaptan of 196 μ L, behind its end seal again, 95 ℃ of heating 24 hours,, at 110 ℃ heat also polymerization 48 hour, make the cylinder that external diameter is 22mm thereafter.

The index distribution of this POF is the index distribution of following W type: the refractive index of cladding part is 1.50, the minimum refractive index of pars intermedia is 1.492, the refractive index of core centre is 1.51.The same light loss that forms higher mode with embodiment 1 is little, the few plastic optical fiber of delay of the light of higher mode.

(embodiment 7)

In embodiment 2, use the CTFE oligomer of PBVE-4M, the 2.4g of 37.6g to replace the PBVE of 20g, the PBVE-4M of 20g, make cladding part.In the making of pars intermedia, fully with embodiment 2 the same manufacturings; In the manufacturing of fiber core part, except the PBVE-4M with 10g change to 9.3g PBVE-4M, the CTFE oligomer of 1g is changed to the CTFE oligomer of 1.7g, with the embodiment 2 identical optical fiber that make 0.75mm.

The index distribution of this POF is the index distribution of following W type: the refractive index of cladding part is 1.34, the minimum refractive index of pars intermedia is 1.328, the refractive index of core centre is 1.355, and the loss of the same light that forms higher mode with embodiment 1 is little, the few plastic optical fiber of delay of the light of higher mode.

The possibility of industrial utilization

The plastic optical fiber that can provide a kind of transmission loss of higher mode few, mode dispersion is little.

Claims

3. plastic optical fiber according to claim 1 and 2 is characterized in that, above-mentioned fiber core part contains and can form by the non-polymerization compound that concentration gradient forms index distribution.

4. according to claim 1,2 or 3 described plastic optical fibers, it is characterized in that above-mentioned fiber core part and above-mentioned cladding part independently contain one or more the polymkeric substance that is selected from acrylic polymers, polystyrene, polynorbornene, polycarbonate, polyimide and the polyester respectively.

5. according to claim 3 or 4 described plastic optical fibers, it is characterized in that above-mentioned non-polymerization compound is one or more the compound that is selected from diphenyl sulfide, Ergol, triphenyl phosphate, dibutyl phthalate and the tricresyl phosphate.

6. according to claim 1,2 or 3 described plastic optical fibers, it is characterized in that above-mentioned fiber core part and above-mentioned cladding part independently contain respectively and do not have the fluoropolymer of hydrogen atom in fact and form.

7. according to claim 3 or 6 described plastic optical fibers, it is characterized in that above-mentioned non-polymerization compound is the fluorine-containing polycyclic compound that has carbocyclic ring more than 3 or 3 or heterocycle and do not have hydrogen atom in fact.

8. according to claim 3 or 6 described plastic optical fibers, it is characterized in that above-mentioned non-polymerization compound is the chlorotrifluoroethylene oligomer.